Nuclear magnetic resonance study of anion and cation dynamics in CsSiH3

JOURNAL OF ALLOYS AND COMPOUNDS

卷:781

Article

Skoryunov, R. V.¹  Babanova, O. A.¹  Soloninin, A. V.¹  Skripov, A. V.¹  Chotard, J. -N.²  Janot, R.²  Tang, W. S.^3,4,5  Dimitrievska, M.^3,6  Udovic, T. J.³ 

[1] Russian Acad Sci, Inst Met Phys, Ural Branch, Ekaterinburg 620108, Russia

[2] Univ Picardie Jules Verne, UMR 7314 CNRS, LRCS, F-80039 Amiens, France

[3] NIST, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA

[4] Univ Maryland, Dept Mat Sci & Engn, College Pk, MD 20742 USA

[5] Carnegie Inst Sci, Geophys Lab, Washington, DC 20015 USA

[6] Natl Renewable Energy Lab, Golden, CO 80401 USA

关键词: Energy storage materials;    Diffusion;    Nuclear resonances;   

DOI  :  10.1016/j.jallcom.2018.12.162

来源: Elsevier

【 摘 要 】

In order to study the dynamical properties of cesium silanide CsSiH3, we have measured the H-1 and Cs-133 nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation rates in this compound over the temperature range of 5-354 K. The results of the H-1 NMR measurements indicate that [SiH3](-) anions in CsSiH3 retain unusually high reorientational mobility down to low temperatures. In particular, a significant narrowing of the proton NMR spectrum due to [SiH3](-) reorientations is observed in the range similar to 10-14 K. The order-disorder (beta ->alpha) phase transition accompanied by the strong acceleration of [SiH3](-) reorientations and by the change in the reorientational mechanism is observed above 200 K; according to the H-1 spin-lattice relaxation data, this transition appears to be gradual. For the high-temperature disordered alpha-phase, the activation energy for [SiH3]( )reorientations is found to be 41(4) meV. The Cs-133 NMR results are consistent with the onset of diffusive motion of Cs+ cations at the frequency scale of similar to 10(4) s(-1) above 300 K. (C) 2018 Elsevier B.V. All rights reserved.

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